① + +
② -( + )
③ + + +
④1- +
⑤ - -
⑥ - + -
10÷2.5= 2.4×0.5= -0.25=
①
② + -
③ + - +
④ + -
⑤2- -
⑥ -( + )
5和9
12和30
17和51
67+28= 960﹣540= 1.6×5= 7.5+2.7=
= = 53÷100= =